Ship hull bottom plating having integral bent back reinforcement



Jan. 29, 1957 J. CUPPLES SHIP HULL BOTTOM PLATING HAVING INTEGRAL BENTBACK REINFORCEMENT 2 Sheets-Sheet 1 Filed Sept. 14. 1950 w NW w 50 |L LLLi L I IT INVENTOR JOSEPH GUPPLES Jan. 29, 1957 J. CUPPLES 2,779,303

SHIP HULL BOTTOM FLATING HAVING INTEGRAL ENI BACK REINFORCEMENT FiledSept. 1%, 1950 2 Sheets-Sheet 2 lNvEN l'OR JOSEPH GUIPPLES ATTORNEYUnited States Patent SHIP HULL BOTTOM PLATING HAVING INTE- GRAL BENTBACK REINFORCEMENT Joseph Cupples, Brooklyn, N. Y. Application September14, 1950, Serial No. 184,796 3 (Ilaims. (Cl. 114-79) This inventionpertains to a new and useful improvement in the manufacture andproduction of structural shapes and it is an object or" thisinvention toprovide structural shapes fabricated in accordance with this inventionwhich may be used in lieu of the currently employed standard rolledshapes, or may be employed as a structural shape forming an integralpart of a plate used in construction work, and in particular wherestructural shapes are employed in conjunction with metallic flat platesor sheets. i The invention also pertains to providing a series ofsections supplementary to rolled sections now in use.

Throughout the invention the expression formed sections will be used forstructural shapes, made in accordance with the invention, incontradistinction to the standard structural rolled shapes. Further, theexpression integral reinforcements will be used throughout thespecification where the stiffening members of a structure, now commonlysecured to the plating either by riveting or by welding, can be formedas an integral part of the plating itself, thus eliminating the extraweight due to riveting, or the extra weight of welding metal, either orboth or which means may be used for the conformal securing of the plateto the structural shape.

.One of the advantages of the invention is that by employing structuralshapes as either formed sections, or integral reinforcements, there willbe a greater degree of accuracy in the ultimate product since there is acomplete elimination of the variations in the thickness of the metalwhen formed in accordance with the teachings of the present invention.

Among the advantages of the present invention are the following:

.To provide a method for executing a 180 deg. backupon-itself bend inplate structures.

To provide an additional series of sections, supplementary to the rolledstructural sections at present in use, and having engineering propertiesof an intermediate nature, thereby providing a more comprehensive andselective choice for engineers and designers.

To reduce weight in metal structures by either eliminating entirely orreducing considerably the necessity for welding and/ or riveting.

To eliminate the dangers coincident with objectionable stresses whichare induced in steel structures by excessive use'of welding.

To eliminate the necessity for stress-relieving in large welded steelstructures by reducing the necessity for weldmg.

To facilitate the sub-assembly phase of construction by makingreinforcement members integral parts of the structure, thereby savingtime and costs during shipping and at final assembly. I I

Engineers employing structural shapes fully recognize that variationsindesigning and detailing must be kept in mind when employingconventional rolled structural shapes since, in production of thestructural shapes, the

roll passes are modified in the wear of the rolls, and the actualdimensions do not always conform to the theoretical, even in the case ofminimum weight sections. By using fiat plates in forming sections anyvariation in dimensions of the section can be contained within therolling limits of the plate.

By employng flat plates or sheets of metal in fabricating the formedsections and integral reinforcements, there is no necessity to beconcerned with the thickness of the.

metal conforming to the theoretical, since flat plates and sheets aremade to conform to a thickness of the plate or sheet. This is differentthan the conformance which would be necessary, for example, in thethickness of the various cross sectional portions of a rolled shape suchas. an I-beam or a channel.

While the present invention will find application in practically everyfield where structural'shapes are now used, one example of a specificapplication will be in the construction of ships which will have atleast a two-fold purpose, namely, in that in the construction of shipsemploying partially prefabricated sections, one or more struc turalshapes which may be alike or dissimilar, can be preformed as an integralpart of the flat plate or sheet all of which can be handled at theforming mill where adequate facilities are available instead of tryingto use make shift methods at the location of assembly of the ships.Further, not only will there be the elimination in engineering overtheconcern of variation in dimensions of the structural shape forpossible reinforcement, but there will be the desired security obtainedby practicing the present invention due to the elimination of the vasttween a light ship and a loaded ship, is the cargo capacity of thevessel. The load-water line is always assigned to a vessel and cannotunder any circumstances be exceeded without breaching the safetyregulations for vessels at sea. However, the light-load line should beas low as possible in order to leave a maximum volume for cargocarryingcapacity. Therefore, whatever is saved in light ship tonnage is gainedin cargo tonnage and the economy and profit of this saving iscontinuously repeated when ever the particular vessel makes a voyage.

By using the present invention with the example of ships, there can be asaving in eliminating the necessity for welding any structural membersand a further advantage of elimination of many of the distortions due tostresses within the structure by reason of the intense concentra-' tionof the high temperatures required by arc welding.

It will be seen from the specification by comparison between theteaching of the present invention, and the conventional rolled shapes,that much less time will be required at the steel mill to fabricate theformed sections whether individually or as part of a plate, than wouldbe required at the shipyard to weld a similar member to the plating plusthe time required originally at the mill to herein, are cheaper tomanufacture, can be produced faster, are stronger in physicalproperties, and are better suited for welded and riveted constructionthan the standard rolled sections.

The present showing are preferred embodiments of the invention but it isto be understood that variatiqns,,

Patented Jan. 29, 1957 changes and modifications may be made withoutdeparting from the spirit of the appended claims.

In the drawings:

' Fig. '1 is an athwartship elevation of a symmetrical half otl'a"transverse bulkhead of a representative vessel looking aft.

Fig. 2 is a representative section of a conventional welded method ofdouble welding a vertical to a horizontal structural member.

Fig. '3 shows the method employed in the present invention forreproducing a condition similar to that shown in the conventional methodshown in Fig. 2.

Fig. 4 is an enlarged view of the section outlined in Fig. 1, indicatedby the character X, according to conventional methods. i

.Fig'. 5. is an enlarged view of a section outlined in Fig. 1, indicatedby the character X, according to the present invention employingintegral reinforcements.

Fig. 6 shows the method of securing the transverse bulkhead. to thebottom shell plating.

Fig. 7, is. an isolated view of the bottom shell plating shown in Fig.6.

Fig. 8 is an isolated view of the transverse bulkhead shown in Fig. 6.

Fig. 9 is a view showing a representative method of groove forming in aplate preparatory to bending.

-;Fig. 10. shows a representative method of multiple grooving a plate.

Fig. ll-the portion of the plate shown in Fig. 9 after the, grooveforming operation is completed.

Fig. 12. shows the plate presented in Fig. 11 after "the 180., bendingoperation is completed.

Fig. 13 is a plate grooved for double 180 bends.

Figure 14 is the plate shown in Fig. 13 with one of the bends formed ata groove.

Fig. 15v is the plate shown in Fig. 13 with both of the bends completed.

-Referring to the drawings, and more particularly to Fig. 1, there isshown a representative athwartship elevation of a symmetrical half of atransverse bulkhead of, a representative vessel looking aft wherein theship 50 has a shell 51 with a longitudinal bulkhead 52 positioned inthe. ship.

Figs. 4 and are comparative sections, respectively, of the conventionalmethod and the method in accordance with the invention as outlined bythe area X of Fig. 1. There is shown the longitudinal bulkhead 52 weldedto the bottom shell plating 53 alongside a longitudinal stiltener5.4..and. a girder 55. all ofwhich are secured to the bottom shellplating '53 by welds 56.

A comparative structure set up in Fig. 5 shows that the girder portion57 and the stiffener portion 58- are formed as an integral reinforcementand are part of the bottom shell plating 59.

.Figs, 2 and 3, are fragmentary comparative representations,reSPQctively, of the conventional welded method of double welding averticalto a horizontal structural member with the similar conditionproduced in conjunction with the teaching of the. present inventionwherein portionsfifland 61abut each other, thereby eliminating the,doublewelds shown at. 5 6. in Fig. 2. The joining seam maybe caulked, toprevent corrosion, shown as 98' inFig. 3.

Figs. 6, 7-, and 8 show the transverse bulkhead 63 having a notch orslot 64 formed therein so that said transverse bulkhead slot may befitted into the slot 65 formed in the integral reinforcement bottomshell plat ing 66, with, the slot 65 being formedthe full width of theflgnge 6,7 and partially in the web 68 so that the edge (ifimay comeflush on the inner surface of the bottorn. shellplating 70sinee theopen'corners where the slot 64' engages the edge 6'9 are rounded to fitthe curved area 71 of the bottom shell plating.

In Figs. 11 to 15 inclusive, there is shown the progressive "steps inmaking'the formed sections and integral Cit reinforcements wherebylongitudinal grooves such as 72 are formed on either one or both sidesof the plate, in separate steps, or in compound operation depending onthe necessary requirements of the particular formed section or integralreinforcements in process of fabrication.

Opposing rollers 73 may be rotatably mounted in the groove formingmachine with the groove roller 74 having a pre-shaped annular flange 75,as part thereof, to form a groove 72. The plate 76 may have the area tobe grooved preheated, or the plate 76 may be rolled cold depending onthe dimensions and physical properties of the plate 76 By utilizing thegrooves 72 as set forth herein, a bend may be formed in a plate as shownin Fig. 11, resulting from the groove being formed in the plate 102 ofFig. 10. The reduction of metal by the grooving process, whether thegroove be formed by rolling as shown in Fig. 9, or by a cutter whereinthe metal is actually removed rather than deformed, permits the 180 bendto be made by a rolling operation so that the surfaces 77 and 78 may besubstantially parallel, which would not be the case if the groove werenot formed in the plate or sheet 76.

In order to hold the reduction in area of section through the bendingplane to an absolute minimum it is suggested that the radius of thesemi-circular area removed from the plate before bending be as small aspossible and still permit the desired result. Since the neutral axis ofthe plate lies somewhere within the inner halfthickness of the material,the radius of the semi-circular section should not exceed one-half ofthis half-thickness. face to the neutral axis then all of the fiberssubjected to, the forces of compression in the critical area will havebeen removed in the process and the intended purpose will have beenentirely exceeded. In conclusion, then, the radius of groove 72 shouldin no case be greater than 25% of the thickness of the plate.

Figs. 13 and 14 are representative of progressive steps in formingopposing 180 bends in a plate 79 after the pair of grooves 72 are formedin the plate shown in Fig. 10 by using a dual groove forming roller, orby using a similar groove forming roller with two passes through thegrooving machine as set forth in Fig. 9.

'It is to be understood that according to the basic teach ing presentedin the invention of groove forming to pro vide integral reinforcementsand formed sections, the.

groove forming machine may have any desired number of groove formingportions on a single roller or separate rollers may be provided whichmay be deposited for the particular section to be formed on either orboth sides- The bend test specimens for bars and shapcsis quite wellstandardized and include that the bars and shapes shall stand being bentcold through 180 without crackiing on the outside of the bent portion.material or under it shall be bent back upon itself without crackingwhile material from to. and includ ing 1 /2" in thicknessshall be bentaround a pin thediameter of which is equal to the thickness ofthespecirnen. Since the bend test mentioned above refers. to. bendingcold the material through 180 without fracture,then,

certainlya preheated plate can be bentback upon itself without anyadverse effects.

When a metal is subjected to heat its molecular struc If radius equalsthe distance from the inner sur,,

Ordinarily for.

ture is thereby rendered sufficiently fluid to permit the shape to beeasily altered. Referring to the back upon itself" bend shown in Fig.12, it may be said that while the fibers on the outside of the bend maybe in tension those on the inside will be in compression. The physicalinterference of these elements coming to bear upon each other can beovercome by removing some of them entirely from the critical areathereby providing space in which other fibers can re-align themselvesand thus relieve the induced forces of compression. If a semicirculararea of inch radius is removed from one surface of the plate at thebending plane the reduction in area of section will only be 0.025 sq.inch. This is, for material of 1%. thickness, a negligible amount whichis of very little importance to the strength of the member. If now theplate is bent back upon itself this open area of 0.025 sq. inch will,theoretically, be distributed throughout a small complete circle ofradius equal to 0.09 inch. In effect this provides a circle ofapproximately 1 of an inch diameter in which the compressed fibers canredistribute themselves and thus relieve the most severe compressiveforces.

In view of the foregoing, it will be seen that by following theteachings of the present invention not only is it possible to makeformed sections comparable to the conventional rolled sections but thatmany other derivatives are possible in structural shapes, regardless ofwhether they are formed sections or integral reinforcements.

There exists at present an enormous capital investment in machinery andmethods for manufacturing rolled sections and it is not the intention towish to eliminate this by substituting formed sections. The intention israther to supplement rolled sections by offering to industry a form moreeasily and more economically manufactured from standard flat plates orsheets. This new form contains many advantages in physical properties,as we shall see, and its addition to the list of standard rolledsections will afford a much wider selective choice for engineers anddesigners.

During the recent war years when precious time and material were beingallocated to effect maximum results the office of production management,in the interests of maximum steel mill production and the conservationof available steel supply, suspended the manufacture of many rolledsteel sections as being non-essential and wisely diverted the materialsto other uses. Formed sections manufactured out of standard rolled platecould have been an ideal substitute in such an emergency.

In longitudinally framed vessels the longitudinal structural memberssecured to the shell-plating must increase in sectional area as weproceed from the deckedge down past the bilge-turn and along the bottomshell to the docking girder. Present practice is to use standard rolledangle progressively up to 8" x 8" which is the largest size rolled.Where greater sections are required flat plate is cut and bent in afianging machine to a 90 deg. right angle shape. In short, rolled anglesections are supplemented with flanged plate sections. The intention inthese notes is to supplement all rolled sections, I beam, H beams,channels, angles, Ts, bulb angles, Zs, with formed sections.

Although steel plate is used as the basis for all calculations containedhere the idea is much broader than this and must include other metalsand alloys as well as other materials such as plastic products, etc.

The present-day practice of welded structural members has effected aconsiderable saving in weight over riveted structural members. The useof integral reinforcements can elfect a further saving by eliminatingthe necessity for welding many structural members. Not only will theweight of weld metal be saved but a further advantage will beelimination of many of the distortions due to stresses set up within thestructure by reason of the intense concentration of the hightemperatures required by arc welding. A further advantage is that thisis an important step in the trendtoward prefabrication of assemblies andas such will be the means of effecting a considerable saving of time.Muchless time will be required at the steel mill to form thereinforcement within the plate than would be required at the shipyard toweld a similar member to the plating plus the time required originallyat the mill to roll the section. I

The following situation should be readily visualized: A vessel is in theprocess of design. The naval architects make up their drawings as atpresent showing welded stiffening members. As the structural drawingsare completed they are submitted to the steel-mill for the purpose ofordering material. The engineers at the mill can easily substitute forthe welded members shown on the drawings suitable and equivalentintegral reinforcements. The plates are prepared at the mill and shippedto the building site ready for immediately assembly; the only additionalrequirement being to secure the butt edges of the prepared plates toeach other.

The idea can no doubt be extended to other fields, particularly in themass production of similar units. For example, in automobile body workand chassis fabrication where a saving in weight would mean greatereconomy in fuel consumption.

From the foregoing it will be observed. that in accordance with thepresent invention it is possible to provide all of the existingstructural shapes as part of integral reinforcements. Further, manyvariations are possible with the present invention so that structuralshapes may be provided in accordance with the engineering design as itadvances in demand.

Not only does the present invention provide equivalent shapes to thosepresently used but permits a great saving in labor at the mill and inlabor of assembly and construction in the field.

By employing the teachings set forth herein prefabrication of manydesigns will be possible, and as was previously pointed out by way ofexample, will have a special application in relation to shipconstruction. In this latter field, the integral reinforcements may beprovided from large plates and may not only include the structuralshapes, but may also take advantage of the fact that the plate itselfmay be curved, angled or bent in any shape or conformation depending onthe requirement of the engineer.

An extremely wide latitude in fabricating formed sections and integralreinforcements is possible by the teachings of the present invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. In a ship hull construction, a bottom shell plating having anintegral longitudinal-extending structural stiffening portion formed ofthe plating bent back upon itself interior of the hull and providingvertical abutting surfaces lying in the outer side of the plating, saidstructural portion being further bent to provide a web and flangerunning coextensively of the plating, said structural portion having aslot through the flange and extending partially down through the webtransversely thereof, and a bulkhead extending transversely through thestructural portion and having a slot in its lower edge fitted in saidslot in the structural portion and receiving the remainder of the web.

2. In a ship hull construction as defined in claim 1, and said webaffording curved areas at the inward bends of the structural portion andsaid open edge slot in the bulkhead being rounded at the opposite sidesto fit the curved areas whereby the lower edge of the bulkhead may bebottomed flush upon the shell plating.

3. In a ship hull construction as defined in claim 1, and saidstructural portion having opposing outer curved areas below the abuttingsurfaces thereof, and closure material extending therebetween.

(References on following page) 8 White Aug. 12, 1930 Weyerbacher Dec.26, 1933 Vass July 9, 1935 Oeckl et a1. June 10, 1941 Krueger June 17,1941 FOREIGN PATENTS Great Britain Oct. 15, 1942 France Dec. 1, 1947France Dec. 1, 1947

